The present invention relates to pump dispensers comprising a container and a dispenser pump for dispensing fluid product from the container.
Pump dispensers, with a dispenser pump mounted on a container of product, are well-known for dispensing fluid products (liquids, creams, pastes) such as cosmetics and medicaments.
Usually the pump body comprises a cylinder as a fixed component. A piston may be on the inner end of the plunger, whose outer manually-engageable end projects from an opening in the body, and which is reciprocable in a pumping stroke to alter the volume of the pump chamber. Therefore, dispenser pumps are typically of a kind in which the pump chamber is defined between a piston and a cylinder. Liquid product enters the pump chamber through a valved inlet and leaves it through an outlet, usually also valved, leading along an outlet channel to a discharge opening. Commonly used valves include ball and flap valves.
Conventionally the plunger projects upwardly from the top of the pump body and the pump chamber inlet is at the bottom of the pump body, drawing product by suction from the container interior beneath. So, for convenience herein the expressions “top”, “upper” etc. are used to refer to positions and directions towards the extended direction of the plunger, and “bottom”, “downwards” etc are used analogously to refer to the opposite direction/position, although this particular orientation is not essential. The dispenser is preferably of a hand-held type, used generally upright.
Usually the pump body comprises a generally cylindrical portion constituting the cylinder in which the piston works. The pump components are typically of moulded plastics materials. A pump spring is usually provided to urge the plunger towards its extended position. Many hand-operated dispensers are of the “movable nozzle” type in which the outlet, outlet channel and discharge opening are in the plunger component. Others are of the “fixed nozzle” type in which the outlet from the pump chamber, like the inlet, is part of the pump body so that the discharge channel and discharge opening do not move when the plunger is operated. The present proposals are generally applicable to pump dispensers of both of these kinds except where the context indicates a specific type.
Preferred aspects of the present disclosure relate to dispensers of the “airless” type, in which the internal volume of the container which supplies the pump reduces as product is dispensed so that remaining product is not exposed to air. Such dispensers may use collapsible containers, collapsible container liners or containers with a follower piston which moves up the container behind the mass of product as its volume progressively decreases.
Measures are usually taken to avoid trapping of air in the container when the dispenser is filled and assembled. Usually a pump module—which may comprise the pump itself (body and plunger) mounted via an adapter component to fit the container opening—is pushed into the container opening after the container has been filled. The lower surface of the pump module may be shaped to dip into the fluid product surface as the pump module is pushed in and snapped or screwed into place, with venting of displaced air through the narrow clearance as the pump and container move into engagement. If the product is over-filled (and some variation is inevitable in practice) there is a risk of product being squeezed out through the gap and this must be avoided. One known measure is to start the filling with the follower piston slightly displaced upwards, so that it can move down to accommodate any excess product.
Our EP-A-1629900 shows a dispenser of a relevant general type, in which the pump adapter is downwardly-dished to form a floor which projects down into the container interior and has the inlet opening for the pump chamber. A steeply inclined peripheral wall of the floor extends up to the snap formations which hold the pump in place.
EP-A-1015341 (U.S. Pat. No. 6,240,979) describes a dispenser module in which a tubular chimney extends down around the pump inlet to ensure that when the pump module is pushed onto the container, a full charge of product is initially forced up into the pump chamber.